Hammer rock drill



Feb. 3, 1959 Filed June 26, 1957 w. D. FISH ETAL HAWER Rock DRILL 4 2 Sheets-Sheet 1 32 Fl G. l. 55329/ 3| 2o 25 INVENTORS,

.JOHN c cufms,

WALTER o. FISH www ' ATTORNEY w. D. FISH ETAL Feb. 3, 1959 HAMMER l ROCK DRILL v. 2 Sheets-Sheet 2 /ILAI lll Filed June 26, '1957 INVENTORS,

JOHN c. CURTIS, WALTER D. F|sH A TTORN EY :IIN

United States Paten-t HAMMER ROCK- DRILL Walter D. Fish, Claremont, and John C. Curtis, Newport,

N. H., assignors to Joy Manufacturing Company, Pittsburgh, Pa., a corporation of Pennsylvania Application June 26, 1957, Serial No. 668,106

11.Claims. (Cl. 121-10).

This invention relates to fluid actuated percussive tools and more particularly to hammer rock drills having iniproved hole cleansing means.

In hammer drilling tools it is a customary practice to supply iluid under pressure to the hole being drilled to clear away the cuttings and, in some instances, the exhaust tluid from the hammer motor is used for hole cleansing purposes. The present invention contemplates improvements over earlier machines in 'that improved exhaust valve means is provided for limitingthe back pressure on the hammer piston as a result of use of the exhaust nid from the motor forA hole cleaning purposes. The exhaust iluid is led from the motor cylinder to the hollow drill steel and a relief valve in the form of an expansible rubber sleeve or ring is provided so that when the pressure of fluid owing to the drill steel reaches a predetermined amount the valve ring will expand and be unseated, allowing excess iluid to escape to atmos-` phere. When the tool is shut down the valve ring contracts against its seat to prevent entry of dirt and water into the internal mechanism.

In the acco-mpanying drawings there are shown for purposes of illustration several forms which the invention may assume in practice.

In these drawings:` i

Fig. 1 is a longitudinal axial section taken through a hammer rock drill of the Ground Hog type.

Fig. 2 is a view similar to Fig. 1,l showing a modified form of construction embodied in a conventional rock drill.

Fig. 3 is an enlarged cross section taken on line 3 3 of Fig. l.

Fig. 4 is an enlarged fragmentary viewtaken o-n the plane of Fig. l, showing the exhaust valve in open position.

Fig. 5 is a cross section taken on line 5--5 of Fig. 2, showing the modified valve structure.

Fig. 6 is a view similar to Figs. 1 and 2, showing a further modiiied construction embodied in a Ground Hog drill.

Fig. 7 is an enlarged cross section taken on line 7--7 vof Fig. 6.

Fig. 8 is an enlarged fragmentary view taken in the plane of Fig. 6, showing the exhaust'valve in open position.

In the several forms of the invention the improved exhaust valve is shown embodied in a hammer rock drill of the conventional pressure fluid actuated type, and is operatively associated with the hole cleansing means of such a drill whereby the building upl of excessive back pressure within the drill motor is prevented.

ln Figs. l, 3 and 4 there is shown a hammer rock drill of the type known as a Ground Hog drill wherein the hammer motor which percussively actuates the drill steel follows the drill bit into the hole being drilled. This motor comprises a tubular casing 1 in which a motor cylinder 2 is arranged. The motor cylinder has a bore (3 containing a reciprocable hammer piston 4 for strikvexterior of the valve sleeve.

"lee

ing repeated blows on the shank 5 of a hollow drill steel 6 which carries a conventional detachable drill bit 7;

The hammer motor is pressure iluid actuated and includes fluid supply ports and passages 8 and 9 and cylinder -exhaust ports 10, all in a conventional manner, whereby the hammer piston is caused to be rapidly reciprocated within the cylinder bore. Leading from a cylinder exhaust port is a longitudinal passage 11 cornmunicating with an annular -chamber 12 surrounding the steel-body and the latter has passages 13 communicating with the hollow interior or axial bore 14 of the drill steel. The drill bit has passages 15 for conducting cleansing Huid from the axial bore to the cutting'face of the bit. The shank 5 of the drill steel is reciprocably guided within a bore 16 of a bushing 17 suitably tted within the front end of the cylinder bore and this bushing has grooves 18 through which fluid may flow from the passage 11 to the chamber 12.

The tubular casing 1 is attached to `the usual rotatable drill rods of the drill and rotation is imparted therefrom to the drill steel so that the latter is rotated as it is percussively actuated. Fitted within the casing is a rotation sleeve 19 having keylike lugs 2li received in keyways or grooves 21 formed on the exterior of the body of the drill steel. The drill steel is guided at 22 for reciprocation within a bushing or sleeve 23 supported within a front housing 24 detachably secured at 25 to the casing.

Now referring to the improved exhaust valve structure it Will be noted that fitted within a bore 26 which also receives the -rearward portion of the rotation sleeve 19 is a valve seat member or sleeve 27 having its hollow interior` 28 communicating rearwardly with thev annular chamber 12. Formed in the circular body ofthis valve sleeve is a series of radial ports 29 and surrounding the circular valve sleeve is an expansible rubber ring or sleeve 30 which when closed contra-cts `tightly against the This rubber sleeve has a forward circular portion 31 held in position between an inclined inner wall 32 of the rotation sleeve and a forwardly facing shoulder 33 on the valve seat member 27. Surrounding this valve is an annular chamber 34- which is connected by a series of radial ports 35 with the exterior of the casing.

During operation of the hammer drilling toolUpressure fluid is supplied through'the ports and passages of the motor cylinder from any suitable source thereby to cause rapid reciprocation of the hammer piston, and the latter as it reciprocates delivers repeated blows Von the shank 5 of the drill steel. During operation or the hammer motor exhaust fluid may ow from the exhaust ports 10 through theV passage 11 and grooves 1S tothe annular chamber 12 and thence from this chamber through ports 13, axial bore 14vandpassages 15'to the cutting face of the drill bit to clear away the cuttings from the bottom of the hole being drilled. ln the event a back pressure builds up within the motor for any reason, as for example when the bit-passages become partially obstructed or clogged, any excess pressure may be Vrelieved to atmosphere through ports 29, past the expanded valve sleeve 30 (see Fig. 4) and ports 35. Thus the back pressure acting on the hammer piston during the hole blowing operation is automatically limited by the provision of the exhaust valve. When the machine is not in operation the rubber valve sleeve will contract tightly against its seat and will act as a check valve to keep water or rock clust from the internal parts of the machine.

ln the modication shown in Figs. 2 and 5 a motor cylinder 40 has a bore 41 containing a reciprocable hammer piston 42 provided with a striking bar 43 for imparting repeated blows to a shank 44 of a reciprocatory anvil or shank-carrying member 45. Coupled at 46 to Vthe member 45 is a drill steel section 47 carrying a conventional drill bit similar to that shown in Fig. 1. A

`usual ratchet controlled, spirally grooved rille bar 48 is connected to the :hammer piston for causing the latter intermittently to rotate as it reciprocates and piston rotation is imparted to the drill steel through grooves 49 on the piston striking bar engaging keylike lugs on a rotation nut 50 secured to a rotation sleeve 51. This rotation sleeve is rotatably mounted in the bore of a front housing 52 suitably secured to the front end of the motor cylinder and this sleeve is clutched at 53 to a rotatable driver 54 rotatably mounted in a bearing sleeve 55 carried within the front housing 52. This driver has usual lugs coacting with lugs 56 on the anvil member 45, to cause the drill steel intermittently to rotate with the driver. Cleansing fluid may be conducted to an axial bore 57 in the anvil member 45 through a conventional cleansing iluid supply tube 58 and uid ows through an axial bore 59 in the steel section 47 and through the bit passages to the cutting face of the bit.

The improved exhaust valve structure of the modification comprises an expansible rubber sleeve valve 60 having an inner beadlike portion 61 held in contracted position within a circumferentially extending groove 62 on the exterior of the motor cylinder. The motor cylinder has usual supply passages 63 and ports 64 and exhaust ports 65 and pressure fluid may flow from an exhaust port through longitudinal passages 66 in the motor cylinder to passages 67 in the front housing 52. The passages 67 are connected by ports 68 through pairs of annular grooves and ports 69 and 70 to the interior of the driver member 54 and thence through ports 71 to the bore 57 and through the drill steel bore to the bit passages. In the event a predetermined back pressure builds up within the motor cylinder during operation of the machine the valve 60 is expanded radially outwardly to permit ow of pressure uid from the passage 66 through radial ports 72 to atmosphere. As in the embodiment rst described the valve 60 when in contracted seated position closes the passages 72 to keep out water or rock dust from the internal parts of the machine.

In Figs. 6, 7 and 8 the further modication of the invention is shown. The rock drill is of the Ground Hog type similar to that shown in Fig. l and comprises a rotatable casing 75 attached to the usual drill rods and containing a motor cylinder 76 provided with a bore 77 containing a reciprocable hammer piston 78. The piston has a forwardly projecting striking bar 79 guided in a bushing 80 carried within a front head member 81, the latter being suitably secured within the motor cylinder.

The striking bar delivers repeated blows to the shank 82 of a reciprocatory anvill or shank carrying member 83, the latter comprising a drill steel by which a drill bit 84 is carried. The piston, the member 83 and the drill bit have suitable passages 85, 86 and S7 respectively for conducting cleansing uid to the cutting face of the bit to clear away the cuttings from the bottom of the hole being drilled. As in the other embodiments the motor cylinder has supply ports and passages 88 and 89 and a cylinder exhaust port 90 and the latter is connected by a longitudinal passage 91, a recess 92 in the head member 81 and passages 93 and radial ports 94 to a chamber 95 into which the striking bar projects, as shown in Fig. 6.

Rotation of the casing is transmitted through a sleeve member 96 and an inner rotation sleeve 97 and the latter has grooves 9S engaging luglike keys 99 on the member 83. Thus, as the drill steel is percussively actuated it is concurrently rotated.

The improved exhaust valve structure of this modification comprises an expansible rubber sleeve or ring 100 held in position at one end by a clamp 101 on the exterior of a valve sleeve member 102, the latter being suitably mounted within the forward portion of the cylinder. The passages 93 and 94 are formed in this valve seat member as shown, and surrounding the valve seat member is an annular chamber 103 connected to atmosphere through radial ports 104. When the back pressure for any reason builds up within the chamber the exhaust valve 100 may expand outwardly, as shown in Fig. 8, to permit How of pressure fluid from the chamber through radial passages 94 and the exhaust passages 104 thereby to eliminate the possibility of excessive back pressures building up within the machine. When the valve is in closed contracted position water and dirt are prevented from obtaining access to the internal moving parts.

As a result of this invention an improved hole cleansing means is provided for a lluid actuated percussive tool for preventing the building up of excessive pressures within the machine during the hole cleaning operation. The hole cleaning lluid is delivered to the cutting face of the drill bit through passages connected to the motor exhaust so that when the machine is operating flow of cleansing fluid to the bottom of the hole being drilled occurs, and in the event the hole cleaning passages become partially obstructed or clogged excessive back pressures are prevented from building up in the machine by the provision of the improved exhaust valve mechanism. The exhaust valve mechanism is relatively simple and .reliable in design and may be incorporated in drilling ,tools of various types with minimum change in design. Other advantages of the invention will be clearly apparent to those skilled in the art.

While there are in this application specically described several forms which the invention may assume in practice, it will be understood that these forms of the same are shown for purposes of illustration and that the invention may be further modified and embodied in various other forms without departing from its spirit or the scope of the appended claims.

What we claim as new and desire to secure by Letters Patent is:

1. In a pressure fluid actuated tool, the combination comprising a pressure fluid motor having a cylinder provided with supply and exhaust passage means and containing a reciprocable hammer piston for percussively actuating a drilling implement, means for conducting pressure fluid from the motor exhaust means to the drilling implement to clear away the cuttings, and exhaust valve means for relieving the pressure in said cleansing iluid conducting means for preventing the building up of excessive back pressures within the tool.

2. A pressure iluid actuated tool as set forth in claim 1 wherein said exhaust valve means includes a valve seat member and an expansible valve member surrounding'said seat member and openable upon a predetermined pressure.

3. A pressure iluid actuated tool as set forth in claim 1 wherein said exhaust valve means includes an exhaust valve surrounding said motor cylinder.

4. A pressure uid actuated tool as set forth in claim l wherein said exhaust valve means includes an annular chamber and passages in the drilling implement communicating with said chamber for conducting pressure tluid from said chamber to the bottom of the hole being drilled.

5. A pressure fluid actuated percussive tool as set forth in claim 4 wherein said piston has a striking portion and said drilling implement has a shank, and said striking bar and said shank of said drilling implement extend into said chamber.

6. In a pressure uid actuated percussive tool, the combination comprising a motor cylinder having a bore containing a reciprocable hammer piston and ports and passage means for supplying pressure fluid and exhausting fluid from the cylinder bore to effect reciprocation of said piston, means for supplying pressure tluid from certain of said portsand passage means to the drilling implement to effect cleaning of the hole bottom during the drilling operation, and exhaust valve means operatively connected to certain of said cleansing fluid supply passage means for automatically preventing the building up of excessive pressures within the tool.

7, A pressure fluid actuated percussive tool as set forth in claim 6 wherein said exhaust passage means includes a chamber communicating with passage means in the drilling implement and an exhaust valve seated against a surface within the tool and openable to relieve predetermined back pressures within the tool.

8. A pressure uid actuated percussive tool as set forth in claim 7 wherein said exhaust valve means includes an expansible rubber sleeve or ring.

9. A pressure uid actuated percussive tool as set forth in claim 8 wherein said rubber sleeve or ring when References Cited in the tile of this patent UNITED STATES PATENTS 1,554,985 Bayles Sept. 29, 1925 

